Environmentally benign anti-icing or deicing fluids

ABSTRACT

Deicing compositions comprised of glycerol-containing by-products of triglyceride processing processes are disclosed.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation application of application Ser. No.12/944,265 filed Nov. 11, 2010, which is a continuation-in-part ofapplication Ser. No. 11/901,301, filed Sep. 17, 2007 now U.S. Pat. No.7,854,856 and issued Dec. 21, 2010, which is a continuation ofapplication Ser. No. 11/114,939, filed Apr. 26, 2005, now U.S. Pat. No.7,270,768, and issued Sep. 18, 2007, which in turn is acontinuation-in-part of application Ser. No. 10/668,674, filed Sep. 23,2003, now U.S. Pat. No. 6,890,451, which issued May 10, 2005.

FIELD OF THE INVENTION

The present invention relates to deicing fluid compositions and methodsfor deicing surfaces and for preventing ice formation (anti-icing) onsurfaces or within fluids. More particularly the present inventionrelates to deicing/anti-icing fluid compositions comprising componentsobtained as glycerol-containing by-products of processing triglyceridesfor the purpose of manufacturing products such as biodiesel.

BACKGROUND OF THE INVENTION

Freezing point lowering compositions are in widespread use for a varietyof purposes, especially to reduce the freezing point of an aqueoussystem so that ice cannot be formed or to melt formed ice. Generally,freezing point lowering compositions depend for their effectiveness uponthe molar freezing point lowering effect, the number of ionic speciesthat are made available and the degree to which the compositions can bedispersed in the liquid phase in which the formation of ice is to beprecluded and/or ice is to be melted.

The most pervasive of the commonly used products for deicing are commonsalt, calcium chloride, magnesium chloride and urea, with common salt(sodium chloride) being the least expensive and most commonly used.Common salt widely is used to melt ice on road surfaces and the like. Inthis manner the salt forms a solution with the available liquid incontact with the ice and thereby forms a solution with a lower freezingpoint than the ice itself so that the ice is melted. Chloride salts,however, suffer from relatively severe drawbacks, such as the harmfuleffects on surrounding vegetation by preventing water absorption in theroot systems, the corrosive effects on animal skin such as the feet ofanimals, clothing, roadways and motor vehicles, and the deleteriouseffects on surface and ground water. Thus, any new method of deicing ornew deicing composition that can reduce the amount of chloride salts, oreliminate chloride salts entirely, would solve a long felt need in theart.

Other inorganic salts also are known to be useful as freezing pointlowering agents such as, potassium phosphates, sodium phosphates,ammonium phosphates, ammonium nitrates, alkaline earth nitrates,magnesium nitrate, ammonium sulfate and alkali sulfates.

Another drawback of certain prior art deicing fluids is their highchemical and biological oxygen demands, which make them environmentallyunfavorable. The glycols are exemplary of deicing fluids thatparticularly suffer from this type of environmental drawback. Thus, anynew method of deicing or new deicing composition that can reduce thechemical or short term biological oxygen demands also would solve a longfelt need in the art.

Typical solutions of low freezing point deicing and anti-icing agentsinclude chloride salt brines, ethylene glycol and propylene glycolsolutions. The use of chloride brines in anti-icing compounds canreduce, although not eliminate, the impacts of chlorides when applied assolids for deicing. Brines and glycol solutions also are employed ascomponents of fluids used to transfer heat in applications where thefluid may be exposed to temperatures below the normal freezing point ofwater. Ethylene glycol solutions are well known for use as coolants forautomobiles and the like in regions where the temperature may fall belowthe normal freezing point of water. Ethylene and propylene glycols areused in relatively large quantities at major airports in northernclimates in order to keep air traffic flowing during inclement weather.The fluids generally are applied to the wings, fuselage and tail ofaircraft and in some instances to the runways to remove ice. However, asmentioned above, these glycol compounds likewise have environmentaldrawbacks and can be detrimental to aquatic life and to sewage treatmentprocesses.

Other prior art deicing fluids, such as alcohols, have toxic effects andhigh volatility particularly in the low molecular weight range. Further,some of these may be the cause of offensive smell and fire danger.Furthermore, mono- and polyhydric alcohols oxidize in the presence ofatmospheric oxygen to form acids, which can increase corrosion ofmaterials.

Due to the problems associated with deicing agents as described abovethere have been attempts to discover even more deicing agents. For,example, Kaes, U.S. Pat. No. 4,448,702, discloses the use of afreezing-point lowering composition and method that calls for theaddition of a water soluble salt of at least one dicarboxylic acidhaving at least three carbon atoms, such as a sodium, potassium,ammonium or organoamine salt of adipic, glutaric, succinic or malonicacid.

Peel, U.S. Pat. No. 4,746,449, teaches the preparation of a deicingagent comprising 12-75% acetate salts, trace-36% carbonate salts, 1-24%formate salts and 1-32% pseudolactate salts that is prepared from a pulpmill black liquor by fractionating the black liquor into a low molecularweight fraction and concentrating the collected low molecular weightfraction to produce the deicing agent.

U.S. Pat. No. 4,960,531 teaches that small amounts of methyl glucosides,i.e., less than 10%, can be employed as a trigger to conventional saltdeicers.

Back et al., U.S. Pat. No. 5,993,684, teach the use of polyhydricalcohols including glycerol in anti-icing or deicing applications, butdoes not teach the use of by-product streams from triglycerideprocessing comprising glycerol. Further, Back et al. teach against theinclusion of potassium and halide salts or the use of glycol informulations.

Parks et al., U.S. Pat. No. 4,501,775, teach the use of lowconcentrations of polyhydroxyalkanes including glycerol, for thespecific purpose of application to coal and mineral ores to insure thatany ice formed is physically weak and will not deter the unloading ofthe coal or mineral ores. Further, Parks et al. do not teach the use ofby-product streams from triglyceride processing comprising glycerol.

Roe, U.S. Pat. No. 4,426,409, teaches the use of polyhydric alcohols,including glycerol, in formulations for the purpose, as in Parks et al.above, of reducing the cohesive strength of particles when frozen.Further, Roe does not teach the use of by-product steams fromtriglyceride processing comprising glycerol.

Special mention is also made of the Sapienza patents, e.g., U.S. Pat.Nos. 5,876,621, 5,980,774, 6,129,857 and 6,506,318, which discloseespecially useful deicing and anti-icing compositions.

Mention also is made of a number of other patents that employ industrialprocess streams in preparing deicing and/or anti-icing compositions.Examples of such patents are Bloomer, U.S. Pat. No. 6,080,330 (desugaredsugar beet molasses); Toth et al., U.S. Pat. No. 4,676,918 (alcoholdistilling waste); Janke et al., U.S. Pat. No. 5,709,812 (whey); Jankeet al., U.S. Pat. No. 5,709,813 (vintner's condensed solubles); Janke etal., U.S. Pat. No. 5,635,101 (corn wet milling process by-products);Bytnar, U.S. Pat. No. 6,468,442 (corn syrup); and Hartley et al., U.S.Pat. No. 6,299,793 (corn syrup).

However, there still exists in the art a need for further improveddeicing and/or anti-icing compositions and methods that areenvironmentally benign and relatively inexpensive to obtain. Preferably,these new and improved compositions are free from or significantlyreduce the use of inorganic salts, are more environmentally benign andare prepared from relatively inexpensive raw materials while stillpossessing desirable freezing point depression properties. Likewise,there also exists a need in the art for new deicing and/or anti-icingagents that can be used in combination with prior art deicing agents,such as inorganic salts or glycols, to substantially reduce the amountof inorganic salts or glycols needed to accomplish thedeicing/anti-icing objectives and, thereby, concomitantly reduce theenvironmental effects of the salts and/or glycols. Surprisingly, it hasbeen found that compositions disclosed herein meet these needs whilefacilitating by-product disposition from production of soaps, fattyacids and bio-diesel. Production of biodiesel is an important strategyto reduce dependence on fossil hydrocarbons for transportation fuel andproviding a means for achieving economic value from the by-productstream is an important element in achieving reasonable productioneconomics.

SUMMARY OF THE INVENTION

The present inventors have found that excellent deicing compositions canbe obtained from the by-product of reactions with triglycerides toproduce monoesters for application to engine fuel commonly known asbiodiesel. Triglycerides, the principal components of animal fats and ofvegetable oils, are esters of glycerol (glycerine), a trihydric alcohol,with fatty acids of varying molecular weight. The triglyceride reactionsof interest involve the use of monoalcohols and include, but are notlimited to, (1) hydrolysis to produce fatty acids for subsequentreaction with monoalcohols to produce monoesters for use as biodiesel,and (2) transesterification reactions with monoalcohols to producemonoesters that can be employed as diesel engine fuel (biodiesel).Production of biodiesel, is of growing importance as part of the effortsto reduce dependence on fossil fuels, and one impediment in this fieldis finding a profitable use for the glycerol containing by-product ofthe reaction. It is therefore a preferred embodiment of the presentinvention to provide deicing and/or anti-icing compositions comprisingby-products of reactions with triglycerides to produce monoesters, saidby-products comprising glycerol.

In a further preferred embodiment of the present invention, thetriglyceride processing by-product deicing and/or anti-icing compositionis combined with an effective freezing point lowering amount of (a) ahydroxyl-containing organic compound selected from the group consistingof hydrocarbyl aldosides; sorbitol and other hydrogenation products ofsugars, monosaccharides, maltodextrins and sucrose; maltitol; glycols;monosaccharides and mixtures thereof, and/or (b) an organic acid saltselected from the group consisting of a carbonic acid salt, a carboxylicacid salt, a hydroxycarboxylic acid salt, a dicarboxylic acid salt andmixtures thereof.

The present invention still further provides a method for reducing theamount of inorganic salt necessary to achieve effective deicing and/oranti-icing, comprising adding to the inorganic salt, an effectivefreezing point reducing amount of the triglyceride processing by-productdeicing and/or anti-icing composition alone, or in combination with aneffective freezing point lowering amount of (a) a hydroxyl-containingorganic compound selected from the group consisting of hydrocarbylaldosides; sorbitol and other hydrogenation products of sugars,monosaccharides, maltodextrins and sucrose; maltitol; glycols;monosaccharides and mixtures thereof, and/or (b) an organic acid saltselected from the group consisting of a carbonic acid salt, a carboxylicacid salt, a hydroxycarboxylic acid salt, a dicarboxylic acid salt andmixtures thereof.

The compositions of the present invention further may comprise a varietyof other materials to enhance the deicing and anti-icing performance,such as, but not limited to, coarse solids to improve vehicle traction,corrosion inhibitors to prevent or reduce vehicular and infrastructurecorrosion and buffers to control the pH of the compositions.

The compositions and methods of the present invention can be applied toa wide variety of surfaces, including both metallic and non-metallicsurfaces of aircraft, which prevents icing, removes frozen water fromthe surface and prevents its reformation. The invention provides for adeicing composition that can be used on airport runways, bridges,streets, other structures including power lines and industrial equipmentsuch as the decks and exposed superstructure of ships, conveyor systems,storage facilities, support systems and the like. Further, thecompositions can be used in heat transfer applications such as, but notlimited to, vehicular radiator systems such as automobile radiatorcoolants, air conditioning systems such as air conditioner fluids andsystems for transferring process heat and systems for recovery of heatfrom process or power generating systems such as process heat transferfluids, and in other applications in which it is vital or desired tomaintain a liquid in the unfrozen state, e.g., as in a fireextinguisher, hydraulic fluids, lavatory fluids or in well drillingfluids, such as those used in drilling for oil and gas. Additionally,the present invention provides for an anti-icing composition that can beapplied to a surface, such as bridges, prior to the onset of icingconditions in order to prevent icing from occurring. Other exemplarysurfaces on which the deicing and/or anti-icing compositions of thepresent invention may be applied include pedestrian walkways, vehicularroadways, highways, bridges, parking facilities, aircraft surfaces suchas wings, fuselage and tail surface, airport runways and taxiways, adeck or superstructure of a ship and weather exposed industrialequipment such as conveyor systems, storage facilities, support systemsand lines for transmission of electric power or electronic signals andexposed machinery and exposed processing equipment and surfaces ofparticles in storage or transport such as coal, ores, sand and gravel.

Still further, the compositions of the present invention can be used asa deicer and/or anti-icer for pre-harvest fruit and vegetable crops,buds of fruit trees or other vegetation, such as, but not limited to,recreational surfaces such as golf course greens.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides novel compositions useful as deicingagents and/or anti-icing agents. The novel compositions of the presentinvention comprise a by-product from one or more ofhydrolysis/esterification reactions and transesterification reactionswith triglycerides for the purpose of producing product monoesters foruse as biodiesel. Considering these reactions in turn;

Hydrolysis/Esterification

Hydrolysis of triglyceride-containing vegetable and animal fats and oilstypically takes place at high temperature and pressure (ca 500 F and 600psi) in a vertical counter-flow reactor with the fat/oil phase flowingupward and the hot water phase flowing downward. Reactor overheadscontain the fatty acid product and the bottoms stream is awater/glycerol stream containing about 12-20% glycerol. The fatty acidsso produced then can be reacted with monoalcohols (containing 1-18carbon atoms) to produce monoesters for use as bio diesel. In thisinvention it is envisioned that the bottoms product from the hydrolysisreactor, containing about 12-20% glycerol can be employed directly as acomponent of a deicing or anti-icing formulation. Alternatively, thismaterial may be at least partially concentrated by evaporation.

Transesterification

Transesterification in this instance involves the splitting of thetriglyceride ester in the presence of a monohydroxy alcohol (e.g.,methanol, ethanol or higher alcohol containing up to 18 carbon atoms) soas to produce monoesters of the fatty acids comprising the originaltriglycerides. It has been found that esters produced in this fashioncan be injected as fuels into diesel engines either pure or blended withfossil diesel. This product has become known as biodiesel. It is alsopossible to produce the monoesters by direct esterification reactionwith the fatty acids separated from the triglycerides by the hydrolysisprocess described above by reacting these fatty acids with the selectedmonoalcohol(s).

The present invention employs the glycerol-containing by-product fromtransesterification reactions, such as biodiesel production, as avaluable component of several deicing and anti-icing formulations. Afactor delaying broader use of bio-diesel fuels has been the need tofind markets for the by-product glycerol to provide income to offset theotherwise high cost of biodiesel fuels. Preferably this market shouldlie outside the traditional uses for glycerol, and should not requirepurification to the standards required for the traditional applications.The present inventors unexpectedly have found an economically viable useof triglyceride processing by-products as a de-icing agent and/oranti-icing agent.

There are three basic routes to production of biodiesel employinghomogeneous systems:

Base catalyzed transesterification of the oil

Acid catalyzed transesterification of the oil

Conversion of the oil to fatty acids (hydrolysis per above) andsubsequent esterification to biodiesel.

The base catalyzed route is the most popular because of the reactionefficiency, mild operating conditions and it requires only simplematerials of construction.

In addition to the homogeneous reaction systems, triglycerides can beconverted to esters in systems employing heterogeneous catalysts. Suchsystems are discussed in Stern, et al (U.S. Pat. No. 5,906,946).

Further, as noted earlier, the esters also can be produced by directesterification of the fatty acids separated from the triglycerides by ahydrolysis reaction with the selected monoalcohols yielding the estersfor biodiesel use as well as a water by-product. In this case theglycerol by-product is produced in the hydrolysis stage as discussedabove.

In general, the catalyst used for transesterification of the oil toproduce biodiesel commercially in homogeneous systems is typically anybase, most preferably sodium hydroxide or potassium hydroxide. Thecatalyst is dissolved in the alcohol using a standard agitator mixer.The alcohol/catalyst mix then is charged into a closed reaction vesseland the oil or fat is added. The system from here is closed totally tothe atmosphere to prevent the loss of alcohol. The reaction mix is keptjust above the boiling point of the alcohol, around 160° F., to speed upthe reaction. Reaction time varies from about 1 to about 8 hours, andsome systems recommend that the reaction take place at room temperature.Excess alcohol normally is used to ensure total conversion of the fat oroil to its esters. Care must be taken to monitor the amount of water andfree fatty acids in the incoming oil or fat. If the free fatty acidlevel or water level is too high it may cause problems with soapformation and the separation of the glycerin/glycerol by-productdownstream. The general biodiesel reaction is shown below:

wherein R′, R″ and R′″ independently are the same or different fattyacid chains associated with the oil or fat, typically palmitic, stearic,oleic and linoleic acids for naturally occurring oils and fats. R is anyhydrocarbyl compound, generally an alkyl group, such as methyl and/orethyl.

Once the reaction is complete, two major products exit: aglycerol-containing by-product and a monoester stream (biodiesel). Eachhas a substantial amount of the excess methanol that was used in thereaction. The reaction catalyst sometimes is neutralized at this step ifneeded. This neutralization will produce the salt of the baseemployed—most often sodium chloride. The glycerol phase is much moredense than the biodiesel phase and the two can be gravity separated withglycerol simply drawn off the bottom of the settling vessel. In somecases, a centrifuge may be employed to speed the separation of the twophases.

Once the glycerol and biodiesel phases have been separated, the excessalcohol in each phase is removed via flash evaporation process or bydistillation such as in a fractional distillation process conducted atlow pressure or under a vacuum. In other systems, the alcohol is removedand the mixture neutralized before the glycerol and esters have beenseparated. In either case, the alcohol is recovered using distillationequipment and is re-used. In this manner, the glycerol containingby-product comprises a transesterification reactor effluent from whichunconverted methanol has been at least partially stripped for recoveryand/or recycling.

In many cases the biodiesel phase is water washed to remove traces ofglycerol, salt, catalyst and unconverted fatty acids and the separatedwater from this step generally is mixed with the glycerol phase. Thisresults in a crude glycerol stream comprising glycerol, salt andMiscellaneous Organics Not Glycerol (MONG). In some cases the crudeglycerol is recovered by a distillation or evaporation step wherein theremaining liquid has a high glycerol, perhaps 80%, or higher. Atatmospheric pressure glycerol boils at 290 C. Operation at such a hightemperatures can lead to a dark, discolored product due to degradationor reaction with any remaining fatty acids. For the purposes of thepresent invention, it may be desirable to remove the alcohol bydistillation while still retaining the bulk of the water in the glycerolcontaining bottoms product. By this procedure, high temperaturedistillation is avoided that would be the case if the bottoms productwere a glycerol concentrate.

The glycerol-containing by-product further may contain salt, catalyst,unreacted fatty acids, unseparated biodiesel and soaps. In accordancewith the present invention this glycerol-containing by-product can beused directly as a deicing and/or anti-icing agent of the presentinvention. In some instances it is desirable to produce an essentiallysalt free glycerol by-product by distillation. In this case a bottomsstream of high salt content, but still containing substantial glycerolis produced. This material also can be employed in formulations fordeicing and anti-icing. In preferred embodiments, the base catalyst thatis employed in the transesterification reaction is neutralized prior touse of the biodiesel by-product as a de-icing and/or anti-icing agent.The base catalyst may be neutralized with any acid, although, generallyin commercial reactions with triglycerides to produce products such abiodiesel, soaps and/or fatty acids, the catalyst is neutralized byaddition of an inorganic acid such as hydrochloric acid. In the practiceof the present invention, the present inventors have found that it ispreferred to neutralize the base catalyst with an organic acid, such as,but not limited to acetic and/or lactic acid. Of course, other organicacids such as, but not limited to carbonic, hydroxycarboxylic,carboxylic and/or dicarboxylic acids can be employed as neutralizingagents in accordance with the present invention.

It also is contemplated within the scope of the present invention thatprior to employing the biodiesel by-product as the deicing or anti-icingcomposition, one or more of the catalyst, the unreacted fatty acids, theunseparated biodiesel or other impurities can be removed by conventionalseparation techniques known to those skilled in the art to provide asubstantially pure glycerol-containing by-product stream. A typicalprocedure is to separate the MONG by reducing the pH of a MONGcontaining stream.

In the case of heterogeneous systems, such as that taught by Stern, etal., a purer glycerin generally is obtained. To control the possibilityof saponification and the resulting production of contaminants in theglycerin product, an esterification reaction with glycerin can beconducted prior to the transesterification reaction essentially toeliminate any free fatty acids in the triglyceride containing feedmaterials. This can be applied in both the homogeneous and heterogeneouscatalyst systems.

In summary, there are several types of glycerin containing by-productstreams obtainable from production of monoesters for biodieselapplication that can be employed in one or more deicing and/oranti-icing applications. These include, without limitation, thefollowing:

(a) Glycerin-Containing Streams from Homogeneous Catalyzed MonoesterProduction:

(i) Crude Glycerin—the by-product from separation of the monoesterproduct from the reactor effluent. In addition to glycerin this streamwill normally contain the salt of the basic catalyst used (typicallysodium chloride), water added from washing of the monoester product andorganic by-products (MONG). Compositions can be about 70-85% glycerin,less than about 20% MONG and about 2-8% salt.(ii) Desalted crude glycerin—The crude glycerin can be distilled toproduce an essentially salt free product. This material can have about75-95% glycerin.(iii) Purified Glycerin—This stream will be either (1) the distillationoverhead if the MONG has been removed prior to distillation, or (2) theDesalted crude Glycerin stream from which the MONMG has been separated.Glycerin content generally will be about 85-95%.(iv) USP Glycerin—If the Purified Glycerin has been prepared to asufficient purity it can be further processed into a product meeting USPspecifications. Critical elements are: <ca 1.7% fatty acids and esters(MONG) as % of glycerin and essentially salt free.(v) Salt Bottoms—The bottoms from distillation of the Crude Glycerinwill have a variable concentration depending on operation of thedistillation process.

(b) Glycerin-Containing Streams from Heterogeneous Catalyzed MonoesterProduction:

(i) Separated Glycerin—The glycerin product separated from the productmonoesters is reported to contain 98% or more glycerin and contain 0.5%methanol, which needs to be removed for most deicing and/or anti-icingapplications. The remaining impurities would be any very small amountsof water introduced with the feedstocks as well as organic compoundssuch as free fatty acids or saponification products.(ii) USP Glycerin—as in the case of glycerin by-product from homogeneouscatalysis, the Separated Glycerin can be upgraded to USP specificationby common techniques such as acidulation for MONG separation.

(c) Glycerin by-Product from Hydrolysis of Triglycerides to Form FattyAcids for Esterification to Monoesters.

(i) Glycerin/water Product—The glycerin by-product from directhydrolysis of vegetable and/or animal oils contains about 12-20%glycerin in a well designed system. In some deicing and/or anti-icingapplications this material can be used directly to add to other deicingmaterials such as inorganic salts, or used instead of water in preparingsuperior non chloride deicing and/or anti-icing formulations such aspotassium acetate/glycerin mixtures.(ii) Dewatered Glycerin—The Glycerin/water Product can be concentratedup to about 85-95% glycerin by multi-stage evaporation.(iii) Purified Glycerin—In turn, Dewatered Glycerin can be concentratedto higher purities by distillation.(iv) USP Glycerin—again as in the previous cases, USP Glycerin can beproduced.

It also is envisioned that the compositions of the invention can beprepared for use in either a liquid or a solid format. For instance, thecompositions can be prepared as a liquid by mixing with water andsprayed or spread on surfaces. Alternatively, it can be prepared in asolid form. Optionally, the solid further may be processed using methodswell known in the art such as, for example, pelletizing, prilling,flaking, or macerating to provide the formulation in a final useablesolid form. Any of the binders known to those skilled in the artoptionally may be present and may either be inert or may be comprised ofcomponents that actively help lower the freezing point and/or provideimproved traction, for example, cinders, sawdust, sand, gravel, sugars,maltodextrins, naturally occurring minerals such as magnesium chloride,trona and mixtures thereof can be used.

It further is envisioned that the compositions of the present inventionalso may comprise corrosion inhibitors. Such corrosion inhibitors mayinclude, but are not limited to, inhibitors comprising salts of gluconicacid or inhibitors comprising salts of monocarboxylic acids.

The amount of triglyceride processing by-product deicing or anti-icingcomposition of the present invention that is required to be effective inthe total deicing or anti-icing agent can vary over a considerablerange. Preferably the amount varies in the range of from 1 to about 100weight percent based on the weight of the total composition. Forexample, we have found that addition of as little as 3% glycerol to a27% magnesium chloride solution can reduce the eutectic freezing pointfrom −35 C to −46 C. In other cases, the formulation may consistentirely of the by-product material. For example a composition of 32%glycerol, 22% NaCl in water has a freezing point of −32 C which issubstantially below the −21 C eutectic of NaCl. In solid formulations,the triglyceride processing by-product deicing and/or anti-icingcomposition may comprise as much as 100% of the final formulation to beadded to the solid carrier material.

It further is contemplated within the scope of the present invention,that in addition to the triglyceride processing by-product, the deicingor anti-icing composition can be combined with an effective freezingpoint lowering amount of an additive comprising (a) ahydroxyl-containing organic compound selected from the group consistingof hydrocarbyl aldosides; sorbitol and other hydrogenation products ofsugars, monosaccharides, maltodextrins and sucrose; maltitol; glycolsglycerol; monosaccharides and mixtures thereof, and/or (b) an organicacid salt selected from the group consisting of a carbonic acid salt, acarboxylic acid salt, a hydroxycarboxylic acid salt, a dicarboxylic acidsalt and mixtures thereof. The amount of additive generally ranges fromabout 0.5 to about 95 weight percent based on the weight of the additiveand by-product.

Certain of the hydrocarbyl aldosides useful in the practice of thepresent invention are known to those of ordinary skill in the art suchas the di- and polysaccharides. Examples of hydrocarbyl aldosides usefulin the practice of the present invention is the glucofuranoside sucrose(table sugar), and maltose and higher polyglucosides.

The hydrocarbyl aldosides also may comprise alkyl aldosides. Alkylaldosides can be prepared, for example, as described in U.S. Pat. Nos.4,223,129 and 4,329,449, which are incorporated herein by reference.Typical of the alkyl aldosides useful in the practice of the presentinvention are alkyl glucosides, alkyl furanosides, alkyl maltosides,alkyl maltotriosides, alkylglucopyranosides, mixtures thereof and thelike.

Other hydroxyl-containing compounds useful in the practice of thepresent invention are sorbitol and other hydrogenation products ofsugars, monosaccharides, maltodextrins and sucrose such as maltitol,xylitol and mannitol, or mixtures thereof; glycols such as ethyleneglycol, diethylene glycol, dipropylene glycol and propylene glycol;glycerols; and monosaccharides such as glucose, fructose and mixturesthereof. These materials are available commercially and are well knownto those of ordinary skill in the art.

The organic salt components useful in the practice of the presentinvention include the carboxylic acid salts, the hydroxycarboxylic acidsalts, dicarboxylic acid salts.

The carboxylic acid salts that are useful in the practice of the presentinvention are likewise available commercially and are known to thoseskilled in the art. Carboxylic acid salts preferred for use in thepractice of the present invention comprise the sodium or potassium saltsof formates, acetates, propionates, butyrates and mixtures thereof. Alsopreferred are potassium acetate and/or potassium formate.

The hydroxycarboxylic acid salts that are useful in accordance with thepresent invention are available commercially and are known to thoseskilled in the art. Preferred hydroxycarboxylic acid salts comprise thesodium and potassium salts of lactic acid such as sodium lactate andpotassium lactate, and of gluconic acid such as sodium and potassiumgluconate. However, any of the cesium, sodium, potassium, calcium and/ormagnesium salts of hydroxycarboxylic acids may be employed such assodium gluconate.

The dicarboxylic acid salts that are useful in accordance with thepresent invention are available commercially and are known to thoseskilled in the art. Preferred dicarboxylic acid salts comprise sodiumand potassium salts of oxalates, malonates, succinates, glutarates,adipates, maleates, fumarates and mixtures of any of the foregoing.

Also useful as a deicing component in certain of the compositions of thepresent invention are the high solubility carbonic acid salts. Preferredcarbonate salts for use in the practice of the present invention arepotassium carbonate, potassium bicarbonate, sodium carbonate, sodiumbicarbonate and cesium carbonate. Potassium carbonate is especiallypreferred.

Also useful as deicing components in certain compositions of the presentinvention are the highly soluble salt forms of sodium formate, potassiumacetate and sodium lactate. In many applications, the addition of thesesalts has been found to provide synergistically unexpected reductions infreezing points.

The following table presents some examples of the combination ofglycerol with other deicing components:

Composition, Example wt % 1 2 3 4 5 6 7 8 Glycerol 50 25 25 25 Potassium25 47 Carbonate Sodium Formate Potassium 25 25 50 Acetate Sodium 25 50lactate Water 50 50 53 50 50 50 50 Freezing −23 −37 −20 −41 −18 −60 −39−32 point, C.Comparing examples 1, 2 and 3, it is noteworthy that the freezing pointof a 50% mixture of glycerol and potassium carbonate is lower that a 50%solution of glycerol or a 47% solution of potassium carbonate. Acomparison of examples 1, 7 and 8 show the same phenomenon with sodiumlactate. In the case of potassium acetate (examples 1, 4, 5 and 6), the25/25 mixture has a freezing point one would expect by a linearinterpolation of the freezing point of the components at 50%. In thiscase, the effect of glycerol substitution is to provide adeicing/anti-icing formulation having a low freezing point,substantially below the freezing point of 25% potassium acetate. Thisimprovement is coupled with the other characteristics provided byglycerol and the other constituents that may be present in a by-productglycerol-containing material. These other characteristics may include,better viscosity and wetting capabilities, and/or corrosion inhibitionproperties.

In certain instances, where the use of the organic acid components ofthe present invention causes the pH of the total composition to be toohigh to meet regulatory or industry specifications, it is contemplatedherein to use a buffering agent to lower the pH to acceptable levels.Suitable buffering agents may be selected from any of the knownbuffering agents. Especially preferred is boric acid. For example incertain highway applications, compositions including potassium carbonateand/or potassium bicarbonate in combination with the triglycerideprocessing by-product of the present invention, may have a pH above 12depending on the exact formulation, and most state highway departmentsprefer deicers having a pH below 12. An effective amount of boric acidor other buffering agent may be added to reduce the pH of the deicingcompounds to less than 12, i.e., to from about 11.5 to about 11.8 orlower, to meet the specifications. Alternatively, during the preparationof the carbonate the pH can be adjusted by continued reaction tobicarbonate or separate addition of same.

The present invention still further contemplates combining thetriglyceride processing by-product deicing composition with otherindustrial process streams useful in deicing and/or anti-icing products.For example, the other industrial process streams may be selected fromany such streams containing the hydroxyl or organic acid compoundsenumerated above including, but not limited to, those selected from thegroup consisting of a grain stillage, grain steepwaters, wood stillage,corn syrups, products of agricultural or milk fermentation processes,products of sugar extraction processes such a desugared sugar beetmolasses and/or desugared sugar cane molasses, hydrogenation products ofsugars, monosaccharides, maltodextrins and sucrose and mixtures of anyof the foregoing. These industrial streams may be employed directly, ormay be treated, such as by alcoholysis to convert the hydroxylcontaining compounds to esters, or by reacting convert the organic acidsto anionic organic acid salts, such as with a caustic.

Generally the triglyceride processing by-product deicing and/oranti-icing agents useful in the practice of the present invention may beused in solid form, liquid form or liquid form mixed with water.

In addition to (a) the certain hydroxyl-containing organic compounds and(b) the certain organic acid salts, it is contemplated by the presentinvention that other organic components may be included in the deicingand/or anti-icing compositions of the present invention. Exemplary ofsuch materials are citrate salts such as sodium citrate; amino acids andtheir salts such as lysine glutamate, sodium pyrrolidone carboxylate andsodium glucoheptonate; lignin components such as lignin sulfonate; boricacid and its salts; sodium gluconate and other gluconic acid salts; andmixtures of any of the foregoing.

In the methods of the present invention, the deicing and/or anti-icingcompositions of the present invention are applied, such as by sprayingfor liquid forms, or spreading for solid forms, onto the surface desiredto be treated. In the case of solid forms, the deicing or anti-icingcomposition can be absorbed or adsorbed onto an inert solid or binder,such as cinders, sand, sawdust, gravel and mixtures thereof; or can beabsorbed or adsorbed onto a solid deicing material such as sugars,maltodextrins, inorganic salts (such as sodium chloride, magnesiumchloride, trona and mixtures thereof) organic salts (such as sodium andpotassium salts of formic acid, acetic acid, lactic acid, calciummagnesium acetate and mixtures thereof); or the solid format can beachieved by processing the composition employing a procedure forconverting a liquid to a solid, such as pelletizing, prilling, flaking,macerating and combinations thereof. In the case of deicing, the surfacealready has ice formed thereon, and the deicing compositions of thepresent invention melt the ice already formed and are further effectivein preventing additional ice formation. In the case of anti-icing, uponlearning of a weather forecast that predicts possible dangerous icingconditions, the roads, bridges, airplanes, runways, growing produce orother surfaces can be pretreated with the anti-icing compositions of thepresent invention in similar manner in order to prevent ice formation onthe treated surfaces.

In situations where some inorganic salts such as sodium chloride,magnesium chloride and calcium chloride can be tolerated, the presentinvention provides an improved method for reducing the amount of salt tobe added to achieve an equivalent or better deicing and/or anti-icingeffect, and thereby reduce the detriment to the environment. Further, wehave found that addition of the glycerol-containing by-products iseffective in lowering the effective use of these chlorides intotemperature regions substantially below the eutectic points of thesimple chloride solutions. For example, we made a mixture of 90% of acrude glycerol stream obtained from soap production, containingglycerol, sodium chloride and some remaining soap and 10% of additionalsodium chloride and determined that the resulting liquid did notencounter ice formation until a temperature of −35 C, considerably belowthe sodium chloride eutectic of −21 C. The addition of salt separatedsome of the dissolved soap, but a small amount of soap remainedproviding for good wetting characteristics of the resulting formulation.

Many variations of the present invention will suggest themselves tothose skilled in the art in light of the above-detailed description. Forexample, the triglyceride processing by-product can be combined with anyindustrial process stream that contains carboxylic acid salts,hydroxycarboxylic acid salts and/or dicarboxylic acid salts in preparingcompositions of the present invention. Additionally, a wide variety ofglucosides, carbonates, hydrocarbyl aldosides, and a variety ofcombinations of the components of the present invention may be employedas additives to the triglyceride processing by-product in thecompositions of the present invention. All such obvious modificationsare within the full-intended scope of the appended claims.

The above-referenced patents, test methods, and publications are herebyincorporated by reference.

1. A method for producing an agent consisting of a substantially pureglycerol-containing by-product stream, optionally comprising water, foraddition to liquids to enable said liquids to function at temperaturesbelow the freezing point of water, and by-product streams comprisingsalt(s) and miscellaneous organics other than glycerol (MONG), saidmethod comprising: a) reacting a triglyceride ester with an alcohol inthe presence of a base catalyst to produce a glycerol phase comprisingglycerol, catalyst, MONG and optionally water and/or unreacted alcoholand a monoester phase that can be processed further in order to beemployed as biodiesel; b) separating said glycerol phase from saidmonoester phase; c) removing substantially all of the alcohol from theglycerol phase; d) neutralizing the glycerol phase with an acid toproduce salts from the base catalyst and to separate the MONG, e)removing said salt(s), MONG, and optionally water from said glycerolphase to produce said agent.
 2. The method of claim 1 wherein thesubstantially pure glycerol-containing by-product stream furthercomprises one or more components selected from the group consisting ofcorrosion inhibitors, hydroxyl containing compounds, organic acid salts,buffers, water and mixtures of any of the foregoing.
 3. A method as inclaim 1 wherein said liquids enabled to operate at temperatures belowthe freezing point of water comprise liquids selected from the groupconsisting of fire extinguisher fluids, heat transfer fluids, engineradiator fluids, oil and gas well drilling fluids, water-based hydraulicfluids, lavatory fluids and mixtures thereof.
 4. A method as in claim 1wherein said liquids that are enabled to operate at temperatures belowthe freezing point of water comprise deicing and/or anti-icing agentsfor use on surfaces selected from the group consisting of aircraftsurfaces, airport runway surfaces, surfaces for vehicular and/orpedestrian use, surfaces of industrial equipment, vegetation surfacesand mixtures thereof.
 5. A method as in claim 1 wherein said liquidsthat are enabled to operate at temperatures below the freezing point ofwater comprise deicing and/or anti-icing agents for use on surfacesselected from the group consisting of coal, ores, sand, gravel, andmixtures thereof.
 6. The method of claim 2 wherein said hydroxylcontaining compounds are one or more selected from the group consistingof xylitol, sorbitol, maltitol, mannitol, glycols, glycerin andhydrocarbyl aldosides.